Many salad dressings, vegetable dips, sauces, and other pourable or spoonable food products are oil-in-water emulsions, which may have different product properties, such as viscosity, physical stability or Theological (flowing) behavior. An emulsion is a preparation established with the use of an emulsifying agent of a deformable liquid (the internal or discontinuous phase) distributed in small globules throughout the body of a second liquid (the external or continuous phase). The continuous phase of the emulsion forms a layer adsorbed around the globules of the discontinuous phase. This modifies the forces of cohesion between these globules, and the forces between these globules and the continuous phase. The globules of the discontinuous phase are held together by London-van der Walls attraction forces, and often form aggregates. Usually, the emulsifier is dissolved, or dispersed, in the continuous phase. An oil-in-water emulsion has oil as the discontinuous phase and an aqueous solution as the continuous phase.
It is beneficial to increase the viscosity of spoonable or pourable oil-in-water emulsion food products because such an increase in the viscosity permits the food products to achieve a desired level of viscosity (i.e., a desired degree of friction between component molecules as they slide by one another) with the use of smaller quantities of oil. The reduced quantity of oil which becomes necessary for the preparation of these food products advantageously results in a cost savings for preparing the food products and, thus, in reduced-cost food products. Additionally, the viscosity of oil-in-water emulsion food products is generally positively correlated with the physical stability of the food products. Thus, oil-in-water emulsion food products having a higher viscosity will generally also be more stable. It is beneficial to control the stability and rheology of food products which are oil-in-water emulsions because such control permits the preparation of food products having enhanced flavor and texture qualities.
Using the formulations, processing steps, and conditions of the methods described herein, in which specified amounts of specified ingredients are processed in specified orders at specified temperatures and reaction conditions, the viscosity of oil-in-water emulsion food products can advantageously be increased beyond the viscosity which would otherwise have been achieved for the food products. This increase in the bulk viscosity can surprisingly be accomplished by lowering, rather than by increasing, the viscosity of the continuous phase (i.e., the serum phase) of the emulsion. In the conventional preparation of oil-in-water emulsions, in contrast, the bulk viscosity of a the oil-in-water emulsion is generally increased by increasing, rather than by decreasing, the viscosity of the continuous phase of the emulsion. Such an increase in such conventional systems is normally achieved by adding hydrocolloids, carbohydrates or similar materials to the continuous phase of the emulsion. These materials bind the water and, thereby, increase the viscosity of the continuous phase, and of the final oil-in-water emulsion.
Because the oil-in-water emulsion food product dressings of the present invention achieve a desired level of viscosity (and physical stability) with the use of smaller quantities of oil than that which would normally be required, the costs for producing these dressings is advantageously reduced.